回复：懒得算， 给个思路 (图)

Your V function is (essentially) the same as my f function that is given in my php program. You can ignore person with speed 1 since he's gonna be the driver anyway. My function is more general than yours in that it takes the speed of the car as a variable as well, while you fixed it as 10. Nonetheless, there is no essential difference.

However, the scheme you designed for 5 people (4 people excluding the slowest) is wrong, if you had not been lazy as you claimed, and had done your homework, you would have found the result you got is even worse than what adamsmth (just realized this is an id from qinghua bbs) had given.